The present invention relates to a method and apparatus for detecting different flaws located at the bottom edge of various type objects such as glassware as well as nontransparent articles in an entirely automatic manner. More particularly, this invention provides a fully automated system for detecting flaws located at the bottom edge of various type moving objects being transported passed a detection station utilizing laser beams as the detection medium.
Automated inspection systems of various types are known to conduct inspections during product manufacture. For example, liquid level inspection is carried out during beverage packaging in both glass and metal containers. Inspection for surface defects in manufactured products is often done manually, however, thereby interrupting overall product manufacture and adding labor costs to the manufacturer. One type manual surface flaw detection method is disclosed in U.S. Pat. No. 3,995,157, assigned to the present assignee, wherein flaws such as cracks, breaks, and other physical discontinuities in metal surfaces are detected by inspection with ultraviolet irradiation after the surface has been coated with a liquid flaw detection medium. A different type of photo detection system is described in U.S. Pat. No. 4,485,308, also assigned to the present assignee, which utilizes X-rays to produce light emission from objects marked or tagged with phosphors and employs photo detection means to read the visible emission thereby produced. This inspection system is suitable for automated postal sorting wherein the postal stamps or imprints contained upon envelopes, postcards, magazines, packages and the like that bear a marking ink containing the phosphor can be identified by the associated photo detection means. Laser gaging systems are also known which optically measure the physical dimensions of various objects such as glass tubing wherein a single laser device provides the measurements. To carry out an illustrative wall thickness or diameter measurement in this manner while the glass tubing product is being manufactured said laser device sweeps the surface of the moving object while cooperative photodetection means provides the particular dimensional information.